1. Technical Field
The present invention relates to a liquid discharge head, a liquid discharge apparatus, and a method for forming the liquid discharge head, and may be included in an inkjet printer. The present invention effectively prevents decrease in reliability with use by fixing a nozzle sheet on a substrate with a predetermined material that has an excellent chemical resistance and sufficient adhesiveness, or more specifically, by fixing the nozzle sheet on the substrate with cyclized rubber or with patternable, adhesive elastic material. Moreover, the present invention may effectively prevent a decrease in reliability by forming walls for liquid chambers and liquid channels with polyimide.
2. Background Art
In general, inkjet printers print desired images on printing stock, such as paper, by discharging ink droplets from a printer head onto the printing stock such as paper.
The printer head included in the printer drives driving elements to change the pressure inside the liquid chambers so that the ink contained in the liquid chambers is discharged from nozzles as ink droplets. The driving elements may be heater elements or piezoelectric elements. Walls of the liquid chambers and the liquid channels are intricately formed with a resin such as epoxy resin or acrylic resin (Japanese Unexamined Patent Application Publication Nos. 61-154947, 62-253457, 3-184868, 6-286149, and 7-214783).
In other words, the printer head is formed by, for example, a semiconductor manufacturing process, wherein, on the semiconductor substrate, driving circuits for driving the driving elements are simultaneously formed with the driving elements for changing the pressure inside the liquid chambers. Then, after a photosensitive epoxy resin is spin coated on the semiconductor substrate, the walls of the liquid chambers and the liquid channels are formed on the photosensitive epoxy resin by photolithography. In another process, a sheet including nozzles (hereinafter referred as a ‘nozzle sheet’) formed by, for example, electrotyping is disposed on the semiconductor substrate.
On the printer head, the nozzle sheet is thermocompressed to the photosensitive epoxy resin that forms the walls of the liquid chambers and the liquid channels.
For known printer heads, the reliability gradually decreases with use.
More specifically, for known printer heads, the resin such as epoxy resin forming the walls of the liquid chambers and the liquid channels erodes and swells with use. This erosion and swelling decreases the adhesive strength between the nozzle sheet and the end faces of the walls. Therefore, in the worst case, gaps form between the nozzle sheet and the end faces of the walls of neighboring liquid chambers, causing crosstalk between these liquid chambers.
In particular, when the nozzle sheet is formed of metal such as nickel or heat-resistant polyimide, the adhesive strength between the nozzle sheet and the end faces of the walls is low from the beginning, causing even more gaps to form and worsening the crosstalk.
When crosstalk occurs between the neighboring liquid chambers of the printer head, the printing performance, such as resolution of the printer, is greatly reduced, making it difficult to print high-resolution images.